This proposal describes feasibility testing of a quantitative molecular assay using monoclonal antibody, fluorescence, and flow cytometry technology for a white blood cell molecule, called 0064. The expression of CD64 increases rapidly on the blood leukocyte neutrophil subpopulation due to molecular activation by inflammatory mediators or cytokines. Quantitative measurement of neutrophil cD64 expression can identify patients with the systemic acute inflammatory response occurring in sepsis, infection or tissue injury. The CD64 assay is anticipated to have medical utility in the triage of patients with infection to appropriate medical therapy, assist in therapeutic monitoring of patients on antibiotic therapy, reduce the unnecessary use of antibiotics, thus minimizing the incidence of antibiotic resistant organisms. The objectives are to optimize use of patented monoclonal antibodies in a 0064 assay, define formulation for assay commercialization, validate manufacturing procedures, improve precision and sensitivity of the assay, confirm utility of a novel quantitative approach to neutrophil cd64 expression using flow cytometry, develop proprietary computer software to improve assay precision, demonstrate feasibility for an stabilized assay control product, and prepare the assay design for subsequent Phase II clinical trials to demonstrate superiority compared to current clinical laboratory tests for sepsis, infection and acute inflammatory diseases.